1. Field of the invention
The invention relates, in general, to semiconductor devices and to the fabrication techniques thereof. More particularly it relates to a semiconductor device in a plastic or ceramic package containing more than one silicon chip or die.
2. Description of the orior art
In the art of fabricating semiconductor devices, beside the development of integration techniques and of relative fabrication processes of the silicon die, new packages, adapted to particular requirements of different types of devices designed for different applications, are also being developed.
The package, that is the encapsulating body housing the semiconductor die and protecting it from the atmosphere as well as providing means for a ssembly and connection on a system's card, must possess requisites which vary with the varying of the scale of integration (more or less pins being required), with miniaturization requirements, and/or with the necessity of providing an adequate heat dissipation capability.
The striving to increase the number of functions performed in the smallest space as possible, besides promoting an ever increasing scale of integration of the monolithically integrated circuits, often imposes delicate compromises in the choice of the particular fabrication technology of the integrated circuits because of poor compatibility among different fabrication techniques. For these reasons, in making complex systems, it is necessary to employ distinct integrated devices for performing certain functions. This implies an increased area requirement on printed circuit cards and an increased number of solderings of external pins of different devices assembled on the printed circuit card.
Lately, where the availability of a sufficient number of external terminals allows it, a technique of mounting two or more silicon dies in a single plastic or ceramic package has been implemented. This technique allows a simea on the printed circuit card but requires the use of a package having a die pad with increased dimensions sufficient to accomodate several silicon dies mounted side by side thereon. This greatly reduce the effective space saving on the printed circuit card.